Lymphoid malignancies, including non-Hodgkin lymphoma (NHL), Hodgkin lymphoma (HL), and multiple myeloma (MM), comprise the fourth most commonly diagnosed cancer in the United States. Dietary and other modifiable behavioral changes may explain part of the striking increase in the incidence rate of NHL during recent decades. Previous epidemiological studies suggest that intake of alcohol, vitamin D, and plant foods are associated with lower risk of several types of lymphoma. Biological evidence of antilymphoproliferative effects of bioactive vitamin D, and anti-cancer effects of dietary antioxidants and certain phytonutrients, support a protective role against lymphoma development, whereas a chemoprotective effect of alcohol is less certain. To date, there have been few prospective studies of diet and NHL risk, and none of HL or MM risk;there has been no prospective investigation of sunlight and risk of these cancers. Therefore, we aim to investigate whether exposure to vitamin D from diet or sunlight;indices of dietary antioxidant intake;consumption of phytoestrogens or isothiocyanates;or consumption of alcohol at various ages is associated with reduced risk of lymphoid malignancies among 110,215 women in the large, prospective California Teachers Study cohort. Between completion of a baseline questionnaire in 1995-1996 and December 31, 2006, 515 cohort members were diagnosed with NHL, 32 with HL, and 84 with MM, making this the largest prospective study of lymphoma to date. We will use multivariate Cox proportional hazards analysis to estimate the relative risks of NHL, NHL subtypes, HL, and MM associated with baseline dietary intake of certain nutrients, phytonutrients, and foods;dietary antioxidant indices;alcohol consumption at various ages;frequency of severe sunburns;age at first severe sunburn;and skin sensitivity to sunlight. In addition, we will use a validated model based on nationwide ultraviolet-B radiation (UVB) measurements to compute average annual UVB exposure according to residential address. Our study's prospective design precludes recall bias, while collection of detailed exposure information enables adjustment for a wide range of potential confounders and modifiers. If vitamin D, dietary antioxidants, and/or phytonutrients indeed decrease the risk of lymphoma, then dietary modification could reduce the considerable morbidity and mortality due to these malignancies and their long-term adverse treatment effects.